Considering that one million patients per year are at risk, human aminoglycoside ototoxicity is not as well understood as it ought to be. This project seeks to develop rapid screening criteria to predict and prevent ototoxicity. In addition, it will determine how radioenzymatic serum aminoglycoside levels best correlate with development of toxicity, what clinical factors predispose to ototoxicity, to determine the incidence of ototoxicity in the various clinical infectious situations reflecting the use of this drug group, and to identify comparable patient groups by computer analysis in an effort to make comparative evaluation of the toxicities of the different aminoglycosides under similar clinical conditions. Human subjects will undergo a detailed history and prospective determination of vestibular and cochlear function by electronystagmography and audiometry respectively. Renal function will be assessed utilizing creatinine clearances and serum BUN. Follow-up evaluation will be performmd in three months to determine development of delayed ototoxicity or recovery from ototoxicity. Data analysis will be performed via the Stanford Center for Information Processing IBM 370/168 computer utilizing program language SPSS, version 7.0.